From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id EB0E57F81 for ; Sun, 17 Mar 2013 23:48:27 -0500 (CDT) Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by relay3.corp.sgi.com (Postfix) with ESMTP id 684FEAC002 for ; Sun, 17 Mar 2013 21:48:27 -0700 (PDT) Received: from aserp1040.oracle.com (aserp1040.oracle.com [141.146.126.69]) by cuda.sgi.com with ESMTP id sD3MM2gd6FDk24sP (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Sun, 17 Mar 2013 21:48:26 -0700 (PDT) Message-ID: <51469C90.1000001@oracle.com> Date: Mon, 18 Mar 2013 12:48:16 +0800 From: Jeff Liu MIME-Version: 1.0 Subject: [PATCH v2] xfs: fix assertion failure in xfs_vm_write_failed() List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: "xfs@oss.sgi.com" Cc: "Michael L. Semon" Hello, Here is the v2 patch for fixing ASSERTION failed at xfs_vm_write_failed() according to Dave's comments, so I added Dave as SOB for credit. Hi Michael, Please kindly try at your at your convenience. Thanks, -Jeff From: Jie Liu In xfs_vm_write_failed(), we evaluate the block_offset of pos with PAGE_MASK which is 0xfffff000 as an unsigned long, that is fine on 64-bit system no matter the request pos is 32-bit or 64-bit. However, on 32-bit system, the high 32-bit in it will be masked off with (pos & PAGE_MASK) for 64-bit pos request. As a result, the evaluated block_offset is incorrect which will trigger ASSERTION failure: ASSERT(block_offset + from == pos); In this case, we can get the following kernel Panic if the CONFIG_XFS_DEBUG is enabled: [ 68.700573] XFS: Assertion failed: block_offset + from == pos, file: fs/xfs/xfs_aops.c, line: 1504 [ 68.700656] ------------[ cut here ]------------ [ 68.700692] kernel BUG at fs/xfs/xfs_message.c:100! [ 68.700742] invalid opcode: 0000 [#1] SMP ........ [ 68.701678] Pid: 4057, comm: mkfs.xfs Tainted: G O 3.9.0-rc2 #1 [ 68.701722] EIP: 0060:[] EFLAGS: 00010282 CPU: 0 [ 68.701783] EIP is at assfail+0x2b/0x30 [xfs] [ 68.701819] EAX: 00000056 EBX: f6ef28a0 ECX: 00000007 EDX: f57d22a4 [ 68.701852] ESI: 1c2fb000 EDI: 00000000 EBP: ea6b5d30 ESP: ea6b5d1c [ 68.701895] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 [ 68.701934] CR0: 8005003b CR2: 094f3ff4 CR3: 2bcb4000 CR4: 000006f0 [ 68.701970] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 68.702011] DR6: ffff0ff0 DR7: 00000400 [ 68.702046] Process mkfs.xfs (pid: 4057, ti=ea6b4000 task=ea5799e0 task.ti=ea6b4000) [ 68.702086] Stack: [ 68.702124] 00000000 f9525c48 f951fa80 f951f96b 000005e4 ea6b5d7c f9494b34 c19b0ea2 [ 68.702445] 00000066 f3d6c620 c19b0ea2 00000000 e9a91458 00001000 00000000 00000000 [ 68.702868] 00000000 c15c7e89 00000000 1c2fb000 00000000 00000000 1c2fb000 00000080 [ 68.703192] Call Trace: [ 68.703248] [] xfs_vm_write_failed+0x74/0x1b0 [xfs] [ 68.703441] [] ? printk+0x4d/0x4f [ 68.703496] [] xfs_vm_write_begin+0x10d/0x170 [xfs] [ 68.703535] [] generic_file_buffered_write+0xdc/0x210 [ 68.703583] [] xfs_file_buffered_aio_write+0xf9/0x190 [xfs] [ 68.703629] [] xfs_file_aio_write+0xf3/0x160 [xfs] [ 68.703668] [] do_sync_write+0x94/0xd0 [ 68.703716] [] vfs_write+0x8f/0x160 [ 68.703753] [] ? wait_on_retry_sync_kiocb+0x50/0x50 [ 68.703794] [] sys_write+0x47/0x80 [ 68.703830] [] sysenter_do_call+0x12/0x28 ............. [ 68.704203] EIP: [] assfail+0x2b/0x30 [xfs] SS:ESP 0068:ea6b5d1c [ 68.706615] ---[ end trace cdd9af4f4ecab42f ]--- [ 68.706687] Kernel panic - not syncing: Fatal exception This patch fix the block_offset evaluation to clear the lower 12 bits as: block_offset = pos >> PAGE_CACHE_SHIFT) << PAGE_CACHE_SHIFT Hence, the ASSERTION should be correct because the from offset in a page is evaluated to have the lower 12 bits only. Thanks Dave Chinner for pointing this out. Reported-by: Michael L. Semon Signed-off-by: Jie Liu Signed-off-by: Dave Chinner --- fs/xfs/xfs_aops.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 5f707e5..a418e17 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -1494,7 +1494,8 @@ xfs_vm_write_failed( loff_t pos, unsigned len) { - loff_t block_offset = pos & PAGE_MASK; + loff_t block_offset = (pos >> PAGE_CACHE_SHIFT) << + PAGE_CACHE_SHIFT; loff_t block_start; loff_t block_end; loff_t from = pos & (PAGE_CACHE_SIZE - 1); -- 1.7.9.5 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs